So...from what I have read up to this point, it looks like this issue has been beaten to death, bandaged & brought back to life, and shot in the neck.

Well, I'm bringing a new one up, because it seems like everyone has some deviation from the original question with this issue.

I have AT&T/Cingular and I DO NOT have a data plan, but every now and then I will want to use the tethering option (Yes I will be charged per Kb used; BTW, what is the exact rate for this?)

I put the initialization string into my "Standard Modem" options for the 8100 modem. I have desktop manager open. I dial *99# without a user/password, and within a few seconds it says "Verifying Username and Password" and stays at that for close to 60 seconds and then hangs up with an error.